Rolling Mill Temperature Control via Cryogenic Cooling
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Solution Overview
Problem
Current aluminum strip rolling processes face challenges in achieving effective temperature control and strip flatness due to heat generation during rolling, leading to equipment overheating, strip staining, and safety issues with kerosene use, as well as inefficiencies in cooling and lubrication systems.
Innovation Solution
Implementing a system with cryogenic fluid applicators and heating devices, divided into zones across the roll width, controlled by a flatness measuring device and processor to vary cooling and heating, replacing kerosene with cryogenic gases or liquids for cooling and using minimal lubricant application upstream of the rolls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water based emulsions are used as rolling coolant and lubricant, then cooling capacity is improved, but strip surface quality deteriorates due to staining
Solution Approach 1:
The invention extracts the cooling function from the lubricant by using a separate water-based coolant system with spray nozzles directed at the rolls, while using a different lubricant (kerosene or alternative) applied to the strip. This separation allows optimal cooling without compromising strip surface quality.
Solution Approach 2:
The invention introduces an intermediary substance (kerosene or alternative lubricant) that performs the lubrication function without the staining problems of water-based emulsions. The kerosene is applied directly to the strip upstream of the mill at controlled flow rates.
2Manufacturing precision
If kerosene is used as rolling lubricant and coolant, then strip surface quality is maintained, but safety and environmental problems worsen
Solution Approach 1:
The invention uses minimal quantities of kerosene (less than 10 liters per minute) solely for lubrication rather than cooling, significantly reducing the amount of hazardous material in the system. The lubricant is applied upstream and does not require extensive recirculation systems.
Solution Approach 2:
The cooling function is extracted from the kerosene system and transferred to a separate water-based coolant system, eliminating the need for large volumes of kerosene and their associated fire safety and environmental risks.
3Temperature
If large flow rates of kerosene are used for cooling, then cooling effectiveness is improved, but system cost and complexity increase
Solution Approach 1:
The cooling function is extracted from the kerosene system and performed by a separate water-based coolant system. This allows effective cooling without requiring expensive recirculation and filtration systems for large volumes of kerosene.
Solution Approach 2:
The invention uses a separate coolant system that copies the cooling function previously performed by kerosene, but with the advantages of water-based cooling (higher specific heat, lower cost, no fire hazard) while applying minimal kerosene only where lubrication is needed.
4Reliability
If separate lubrication and cooling systems are implemented, then lubrication efficiency is improved, but system complexity increases
Solution Approach 1:
The invention segments the lubrication and cooling functions into separate systems: water-based coolant spray nozzles for cooling the rolls and a separate lubricant application system for lubricating the strip. This segmentation improves the efficiency of each function while maintaining manageable system complexity through modular design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances temperature control and strip flatness, reduces safety risks, environmental impact, and operational costs by eliminating kerosene-related hazards, improving production efficiency, and minimizing coil staining and annealing time.
Implementation Method 1
a plurality of cryogenic fluid applicators arranged to direct a cryogenic fluid to one or more of a plurality of zones on the surface of at least one of the rolls
Implementation Method 2
By varying the cooling effect across the roll's width, it is possible to impart different degrees of thermal expansion to different parts of the roll, thereby providing a mechanism to compensate for local variations in roll gap
Data Source
AI summary
For controlling the flatness of the strip during the rolling of aluminum strip or foil, the system consists of a full width bank of cryogenic roll cooling devices acting on the roll(s) and a full width bank of roll heating devices also acting the roll(s). Both or either of the cooling and heating banks are divided into individually controllable zones. A process automation system controls the action of the cooling and heating banks via feedback from a strip shape meter and/or a predictive process model, in order, by thermal growth/contraction, to create the best roll profile for rolling flat strip.